Field
This disclosure relates generally to electronic device packaging, and more specifically, to fanout wafer level packaging of electronic devices.
Related Art
Fanout wafer level packaging (FO-WLP) processes typically entail the formation of redistribution layers over the surface of a die package, which includes a molded package body in which one or more microelectronic devices are embedded. For example, FO-WLP processes may be used to produce System-in-Package (SiP) types of device, in which multiple microelectronic devices, such as semiconductor die carrying ICs, micro-electromechanical systems (MEMS), optical devices, passive electronic components, and the like, are embedded in a single package that is both compact and structurally robust.
In a FO-WLP device, the redistribution layers provide electrical interconnection between contact pads located on the embedded microelectronic devices and a contact array, such as a ball grid array, formed over a surface of the completed FO-WLP package. In this manner, the redistribution layers allow the contact pads to have a relatively tight pad-to-pad spacing or pitch, while still providing a comparably large surface area over which the contact array can be distributed or fanned-out. To produce the redistribution layers, one or more layers of dielectric or passivation material are initially deposited over the embedded microelectronic components and cover the contact pads. In one conventional approach, a separate via is etched through the dielectric layer to expose a portion of each contact pad, metal plugs or other conductors are then formed in each via to provide ohmic contact with the contact pad, and then a circuit or interconnect line is formed in contact with each conductor.
Conventional FO-WLP devices include only a single plane of microelectronic devices embedded inside the molded package body. Accordingly, given miniaturization limits on the microelectronic components, increasing the number or complexity of the embedded components results in an increase in the FO-WLP device footprint. With the ever-present desire to reduce, rather than increase, device footprints, it is desirable for there to be further improvement in the device density in FO-WLP devices.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The figures are not necessarily drawn to scale.